Dehairing apparatus and method



July 8, 1958 E; J. STRANDINE ETAL 2,841,

DEHAIRING APPARATUS AND METHOD Filed Oct. 20, 1955 EZDO/V STRAND/IVEFHA/V675 6. CO/V/V/CK BY A ATTORNA-"V Unite States Patent DEHAIRINGAPPARATUS AND METHOD Eldon J. Strandine and Francis G. Connick, Chicago,Ill., asslgnors to Swift & Company, Chicago, 111., a cor poratlon ofIllinois Application October 20, 1955, Serial No. 541,635

7 Claims. (Cl. 19-2) This invention relates to an apparatus and methodfor removing hair or wool from animal pelts. More particula rly, theinvention relates to a method and apparatus especially adapted forremoving wool from sheepskin in a largely automatic fashion.

The conventional method of removing wool from sheepskin necessitatespainting the pelts on the flesh side with a suitable depilatorysolution, for example, a mixture of sodium sulfide, calcium hydroxideand water. After a pelt has been treated in this fashion, it isordinarily allowed to stand for a considerable period of time under highhumidity conditions. This treatment destroys the wool roots togetherwith a portion of the wool fiber adjacent the roots and frees the fiberfrom the slat to which it adheres, thereby making the final wool removalstep a relatively easy one. At this point, the wool is so loosened thatit may be manually pushed or lifted from the pelt.

A number of other methods have been proposed at one time or another. Forexample, the pelts, either painted or not, may be allowed to stand forsuch a period of time that the hide and flesh deteriorate to a pointwhere the Wool is largely free. Some methods involve the use of variousproteolytic enzymes, such as those of the pancreas glands or molds.These methods also result in damage to both hide and wool of one degreeor another. Less destructive or milder reagents may be used to loosenwool or hair but more energy is then required to pull the mass of fibersfrom the hair follicles. It has been suggested that wool removal mightbe facilitated by employing a solution of ammonium hydroxide rather thanstrong alkalis or acids which have been applied as depilatories in thepast. While this type of treatment does partially loosen the wool fromthe hair follicles, it is ordinarily inadequate, at least where methodsinvolving hand pulling are practiced. This is true unless excessivequantities of the ammonia solution are used. Cost considerations plusthe fact that the use of large quantities, even of a relatively weakalkali, can result in damage to the fibers, have discouraged widespreaduse of processes of this type.

It is, therefore, an object of this invention to provide an apparatusfor removing hair or wool from pelts which eliminates the necessity forpainting of the pelts with strongly acidic or alkaline depilatories.

It is a further object of this invention to provide a novel process forremoving hair from hides and particularly sheepskins wherein moderatequantities of a solution of ammonium hydroxide adequately serve as theagent for loosening the hair from the follicles.

A further object of this invention is to provide an apparatus which iscapable of stripping hair from hides and skins in a largely automaticfashion and is also capable of separating fibers from greasy orsemi-fluid extraneous material.

Additional objects and advantages of this invention if not specificallyset out will become apparent to one 2,841,829 Patented July 8, 8

skilled in the art during the course of the following description.

The present invention relates broadly to an apparatus and method forgripping wool and stripping it from the skin in which it is imbedded.The apparatus comprises a plurality of rollers mounted in pairs andoperatively associated with conveyor means which feed wool containingpelts to the various rollers. The first pair of rollers move at aboutthe speed of the conveyor and are closely enough placed one above andone below the conveyor to tightly hold and thereby control the movementof the pelt being treated. Immediately beyond the first pair of rollersis placed another similarly mounted pair, the lowermost roller of whichturns with the conveyor at a speed equivalent to that of the first pair.The roller positioned above the conveyor moves at a speed somewhatgreater than that of the other rollers so that it exerts a pulling forceupon any hair or wool which it touches. The latter roller is provided atspaced intervals about its surface with a plurality of longitudinalridges or fins which aid in gripping and pulling the wool to beloosened. Another roller on top of the conveyor belt, near the end ofthe conveyor, turning with the speed of the conveyor compresses andholds the pelt tightly against the conveyor.

A third pair of rollers are mounted at the discharge end of the conveyorand, like the others, are disposed transversely of the moving conveyorsurface. Preferably these rollers are placed at the point at which theconveyor belt turns downwardly before beginning its return to theforward end of the dewooling apparatus. However, obviously these rollersmay be located at some other point adjacent the outer surface of theconveyor. These rollers are substantially contiguous along one entirelongitudinal surface and must be close enough to the conveyor to gripand apply a pulling force to the partially loosened wool. Thepelt-bearing conveyor does not pass between these rollers. Theirfunction is simply to grip and pull upon the wool while allowing thecleaned or stripped pelt to drop freely upon a second conveyor or into asuitable collecting device. These rollers are so closely placed relativeto one another that the slat does not pass between them. It has beenfound that the prevention of the passage of the slat between these tworollers may be effected by constructing the lowermost of a rigidmaterial such as steel and the upper roller of a resilient substancesuch as rubber.

One particularly important use for the machine is in connection withhide treatment with a mild depilatory such as a weak solution ofammonium hydroxide which loosens the hair or Wool only moderately (to anextent that it is difficult to separate hide and fiber by hand). Theselection of such a weak depilatory avoids injury to both hide and fibersuch as might result where acid or alkali hydrolysis, heat hydrolysis ordigestion methods are employed. A more complete understanding of thedevice may be gained by reference to the following description andaccompanying drawings.

In the drawings:

Figure l is a side View in perspective of an apparatus embodyingfeatures of the present inevntion.

Figure 2 is a schematic side elevational view through the apparatusillustrating the operation of the rollers and conveyor.

Figure 3 is a transverse vertical sectional view through the ridgedroller.

Figure 4 is an isometric view of a flutter blade roller which maybesubstituted for the pulling roller-scrapers shown in Figure 1.

Referring now to the drawings in which like characters refer to likeparts throughout: the apparatus and driving means comprise generally aframe or table 10 resting upon suitable legs or similar support means11. Conveyor belt 12 is mounted by means of supporting rollers 13 and 14having their respective shafts extending through and journaled inaxially aligned bearings mounted in the sides of the table 10. Theconveyor supporting roller 14 is driven by means of pulley 15 to whichis attached belt 16 which in turn is connected to pulley 17 of electricmotor 18. The uppermost portion of conveyor belt 12 is partiallysupported by small diameter traversely mounted rollers 19, suitablybracketed or similarly mounted upon table 10. Each of the idler rollers20 are also journaled in bearings axially aligned with one another inthe sides of table 10. These idler rollers provide support for thelowermost portion of conveyor belt 12.

Beyond the feed end of the apparatus are two cooperating coextensiverollers 21 and 22 (shown in Fig. 2), the respective shafts of whichextend through axially aligned bearings mounted in the table sides.Roller 21 is positioned just above the upper surface of conveyor belt 12and roller 22 just beneath. The two are closely spaced so that if a skinis placed upon the conveyor surface and fed between them, it will besecurely held in place. In other words, these two rollers operate in afashion similar to the wringer rollers on an ordinary washing machine.Roller 22 is provided with a suitable gear 23 mounted at one end thereofon the extending portion of its shaft. Similarly, roller 21 is providedwith a gear 24 also fixedly attached to the extending portion of itsshaft. These two gears mesh and coact so that the two rollers may becaused to turn toward one another on the application of power to eitherone. In the apparatus shown in Fig. 1, gear 23 is provided with a pulley25 also fixedly attached to the extending portion of the shaft of roller22. This pulley is in turn connected through belt 26 to the pulley 27 ofmotor 18.

Just forwardly of roller 22 is a similarly positioned roller 28. Thisroller is similar to roller 22 in that it is mounted beneath theconveyor belt surface and is contiguous thereto. It is also held inposition by a shaft journaled in suitably axially aligned bearings whichare in turn mounted in the table sides. On one end of the shaft is agear 29 to which is connected a pulley 30 driven by means of previouslymentioned belt 26. Mounted just above this roller and above the conveyorbelt is another roller-like member 31 which in a fashion similar to theothers previously discussed, is journaled in bearings mounted in thesides of the table 10. This roller, however, is constructed differentlythan the others in that it is provided with a plurality oflongitudinally extending ridges or fins 32 which extend radially aboutthe surface. The ridges, strips or fins are constructed of steel orother rigid material. They run parallel to the roller. Mounted on theoutwardly extending portion of the shaft carrying roller 31 is arelatively small gear 33 which meshes with gear 29 of roller 28 in sucha fashion that rotation of the lowermost roller drives the upper. Thisuppermost gear 33 is of a relatively small diameter so that it ispossible to drive roller 31 at a greater speed than that attained at anygiven time by the roller 28.

Attention is now directed to the right hand end of the table, thedischarge end. Two substantially coextensive rollers 36 and 37 aremounted in parallel fashion so that they touch one another along a lineextending the entire length of the longitudinal surface of each. Eachhas shafts journaled in bearings mounted on the sides of table 10.Positioned on the one extending end of each of these shafts arecooperating gears 38 and 39. The uppermost of these, 38, meshes withgear 40 mounted on the outwardly extending portion of the shaft ofconveyor roller 14. Rollers 36 and 37 are preferably mounted oneslightly above the other almost in contact with the conveyor belt at thepoint at which the conveyor first turns downwardly prior to starting itsreturn trip to the feed end of the stripping machine. It may beobserved,

however, that rollers 36 and 37 may be positioned at some other pointnear the discharge end of conveyor 12 as long as the plane to whichrollers 36 and 37 are mutually tangent along their line of contact, ismaintained perpendicular to the conveyor surface along the line ofintersection of that plane and the conveyor surface. Both rollers moveat a relatively high speed when power is supplied to pulley 15, becauseof the fact that gear 40 transmits such power to gear 38 and in turn togear 39.

Suitable scrapers 41 and 42 are mounted on table 10. These scrapers restagainst the surfaces of rollers 36 and 37 and serve to dislodge any woolor hair which adheres to such rollers. As an alternative to scrapers 41and 42 the apparatus shown in Figure 4 may be used. The figure shows aflutter blade roller constructed of a Square or cylindrical piece ofmetal or wood tubing 43 to which rubberized belting material 44 is heldwith bolts or rivets 45. The blades 44 are flexible and bend readily.The unit is mounted on a shaft 46 which may be journaled in bearings(not shown) in such a position that either or both of scrapers 41 and 42are replaced. Of course, two such flutter blade units, driven bysuitable belting connected to a motor may be employed, one for eachroller 36 and 37.

Also preferred is a holding roller 47, the shaft of which is journaledin frame 48. This roller needs no power source other than the conveyorbelt with which it is frictionally engaged. Its function is to tightlygrip the skin with the aid of roller 14, just before it reaches thepulling rollers 36 and 37.

As mentioned heretofore, limited pretreatment of the skins to loosen thewool or fiber somewhat is ordinarily necessary. A preferred processinvolves treatment with a weak ammonium hydroxide solution. For example,the pelts may be soaked overnight in a 0.2 to 0.8 molar solution ofammonium hydroxide; the ratio of weight of solution to skin weight beingabout 8 to 1. If intermittent agitation is provided, the soaking timemay be reduced to about four hours. The temperature of the bath willordinarily be about 50 to F. Following the chemical loosening step, warmwater may be used to heat the skin to to F., i. e., above the meltingpoint of the natural greases of the skin.

The following example is for purposes of illustrating a typical chemicalpretreatment operation. However, it is to be borne in mind that theinvention is not limited to this specific type of chemical prelooseningand that any process which does not destroy hair and skin may be usedfor preparing the skins for treatment in accordance with the invention.

One thousand pounds of sheep skin were immersed in 8,000 pounds of 0.5molar NH OI-I solution. The bath temperature was held at 6070 F. and thesoaking continued for 16 hours. The skins were then removed from the vatand rinsed for 20-30 minutes in 110 F. water. The skins were drained andfed through the machine in the fashion described in detail below.

The hide or pelt to be dehaired or dewooled after being pretreated asjust outlined is placed upon the feed end of conveyor 12. The hair onthe pelt extends upwardly. Power is transmitted from the motor 18through belt 16 to roller 14 which in turn causes the conveyor to moveforward. The pelt is advanced to rollers 21 and 22, which, by means ofpower supplied from motor 18 to pulley 25 and because of the fact thateach roller is connected to the other by means of the gearing mounted onits extending shaft, rotate at about the speed of the conveyor. Therollers are so closely placed that they in fact aid in moving theconveyor in a forward direction. Because of their close proximity one tothe other, they also grip and securely hold the pelt being dewooled;that is, the pelt necessarily advances only at the speed of the conveyorand will not slip upon the conveyor surface while it is between theserollers. As soon as the lead edge of the pelt has passed from beneaththese holding rollers 21 and 22, it passes beneath pulling roller 31which cooperates with the supporting roller 28. This lower roller 28rotates at about the speed of the holding rollers 21 and 22. The gear 29mounted on the extending shaft of roller 28 meshes with gear 33 which isin turn mounted upon the extending shaft of pulling roller 31. Becauseof the fact that gear 33 is somewhat smaller than gear 29, the ridgedpulling roller moves at a somewhat greater speed than either theconveyor, skin or the other rollers. The circumferentially mountedridges 32 therefore exert a pulling action upon the hair or wool on theskin surface whereby the hair or wool is substantially loosened from thefollicles and many of the fibers are pulled almost free. After passingthrough these cooperating rollers 28 and 31, the skin bearing thepartially loosened fibers is advanced by conveyor belt 12 to the end oftable at which point the belt turns in a downward direction prior tobeginning its return to the feed end of the dewooling apparatus. Aspreviously mentioned, the rollers 36 and 37 are mounted in parallelfashion transversely of the conveyor belt in close proximity to the arcdescribed at this point by the conveyor belt and supporting roller. Theleading edge of the hide, therefore, passes in a downward directionbetween rollersupported belt 12 and rollers 36 and 37 and the trailingportion is held by roller 47 cooperating with roller 14. Cooperatingrollers 36 and 37 are rotated toward one another by means of gears 38and 39 as well as driving gear 40, pulley 15, belt 16, and motor 18.Their direction of rotation is shown in Fig. 2. Their action is to gripthe partially loosened hair or wool and completely separate it from theslat. The two rollers are so closely placed that they firmly grip theindividual fibers while preventing passage of the pelt itself. Theirrelatively high rate of rotation causes them to contact virtually allhairs extending from the hide surface. Since the skin is generally in adampened condition at the time that it is fed into the dewoolingmachine, it has been found that the fibers will mat and adhere, usuallyin relatively large clumps, to the surfaces of these two pulling rollers36 and 37. For this reason, scrapers 41 and 42 are mounted at an acuteangle to the roller surfaces. Alternatively, one or more rotatingflutter blade rollers may be used to clean the pulling roller surfaces.

It has been found that the pulling rollers 36 and 37 are most effectivein preventing passage of the slat if the lowermost is constructed ofrigid material such as steel. The uppermost roller 36, however, ispreferably of a resilient material such as rubber. An effective grippingaction is thereby provided.

After completion of the dehairing operation, the conveyor 12 drops thecleaned slat into a suitable receptacle or onto a conveyor and the woolfibers are similarly collected, cleaned, and further treated.

As alternatives to holding roller 47 other devices may be used to insurethat the hide is pressed tightly against the conveyor 12 and is notpulled through rollers 36 and 37. For example, a series of parallelwires may be tightly strung on top of and against the conveyor belt atthe point where it contacts roller 14. The wires are placed at rightangles to the rollers and, While generally following the contour toroller 14, are spaced from the conveyor belt at the feed end so thatskins will be guided between said wires and roller 14. The wires movecodirectionally with the conveyor and thereby squeeze the wool or fiberbearing skin tightly against the conveyor as it passes the pullingrollers 36 and 37. The fibers slip between the wires and are gripped andfreed from the slat by these pulling rollers.

Preferably, conveyor belt 12 is provided with two rectangular holes 51.In one manner of operation of the machine the two hind shanks of thepelt are thrust through these holes so that as the pelt is beingstripped of its Wool by the action of rollers 36 and 37, it is firmlyheld against 6 roller 14 by means of the two hind shanks being caughtbetween roller 14 and the inside of the belt 12. The hind shanks of thepelt are fed through the machine in the leading position and theremainder of the pelt trails behind.

A holding roller 49 is advantageously provided to frictionally engagethe partially stripped pelt and to maintain the tension necessary tohold the stripped portion of the pelt against roller 14 as the trailingportion of the pelt is being stripped. This is desirable since theshanks held in place by roller 14 become disengaged from the roller assoon as the belt and roller depart at their point of tangency and thepulling force exerted by the trapped shanks is no longer in existence.Roller 49 is driven by a gear 50 which in turn is driven by gear 40.

Roller 49 may be eliminated and clamps substituted in place of holes 51for holding the pelt firmly in place at all times. Another alternativeis to make roller 14 so large that the pelt would be completely strippedof wool before the shanks are released at the point of tangency.

It is seen that by the use of the apparatus of this invention, it ispossible to effectively dehair or dewool pelts which have been onlysubjected to the action of a mild depilatory since an effective grippingand pulling action is achieved. The necessity for strong alkalinematerials which destroy a portion of the wool while they are looseningthe fibers from the hair follicles is eliminated. Furthermore, once thepelt has been fed to the lead end of the machine, the operation iscompleted in a largely automatic fashion. No further hand manipulationis necessary in separating the fibers and slat from one another.

Obviously, many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim: I

1. Apparatus for dehairing skins comprising: means for abraiding andloosening the hair on said skins; means for controlling the motion ofsaid skins while they are being subjected to the action of the abraidingand hair loosening means; and means following said loosening means forgripping and applying a pulling .force to said hair while simultaneouslypreventing movement of the skin codirectionally with the said pullingforce.

2. Apparatus for dehairing skins comprising: a pair of rollers rotatablein opposite directions; a second pair of rollers closely spacedlaterally from said first pair of rollers, each roller being rotatablein the same direction as the corresponding roller of the first pair ofrollers; one of said second pair of rollers having a roughened surfaceadapted to loosen the hair adhering to skin surfaces; means for rotatingthree of the four rollers at substantially identical speeds; means forrotating said rough surfaced roller at a speed in excess of the speed ofthe other three rollers; conveyor means operatively associated toadvance a skin between the rollers of each pair sequentially; and athird pair of coacting rollers positioned adjacent the discharge end ofsaid conveyor means to grip and apply a pulling force to the hair whilesimultaneously preventing movement of the skin codirectionally with thesaid pulling force.

3. Apparatus for dehairing skins comprising: a pair of substantiallycoextensive rollers normally adjacent one another and rotatable inopposite directions; a second pair of substantially coextensive rollersnormally spaced adjacent one another, each roller being rotatable in thesame direction as the corresponding roller of the first pair of rollers,and closely positioned laterally from the first pair in a planesubstantially parallel thereto; one of the second pair of rollers havinga roughened surface adapted to loosen hair adhering to skin surfaces;means for rotating three of the four rollers at substantially identicala speeds; means for rotating said rough surfaced roller at a speed inexcess of the speed of the other three rollers, conveyor meansoperatively associated to advance a skin between the rollers of eachpair sequentially; and a third pair of substantially coextensive rollerspositioned adjacent said conveyor means at the discharge end thereof togrip and apply a pulling force to hair While simultaneously preventingmovement of the skin codirectionally with the said pulling force.

4. Apparatus for dehairing skins comprising: a pair of substantiallycoextensive rollers normally adjacent one another and rotatable inopposite directions; a second pair of substantially coextensive rollersnormally spaced adjacent one another, each roller being rotatable in thesame direction as the corresponding roller of the first pair of rollers,and closely positioned laterally from the first roller pair in a planesubstantially parallel thereto; one of said second pair of rollershaving a plurality of circumferentially spaced ridges adapted to rubagainst and loosen hair adhering to skin surfaces; means for rotatingthree of the four rollers at substantially identical speeds; means forrotating said ridged roller at a speed in excess of the speed of theother three rollers, conveyor means operatively associated to advance askin between the rollers of each pair sequentially; and a third pair ofsubstantially coextensive rollers positioned adjacent said conveyormeans at the discharge end thereof to grip and apply a pulling force tohair while simultaneously preventing movement of the skincodirectionally with the said pulling force.

5. Apparatus for dehairing skins comprising: a pair of substantiallycoextensive rollers normally adjacent one another and rotatable inopposite directions; a second pair of substantially coextensive rollersnormally spaced adjacent one another, each roller being rotatable in thesame direction as the corresponding roller of the first pair of rollers,and closely positioned laterally from the first roller pair and in aplane parallel thereto; one of second pair of rollers having a roughenedsurface adapted to loosen hair adhering to skin surfaces; means forrotating three of the four rollers at substantially identical speed;means for rotating said rough surfaced roller at a speed in excess ofthe speeds of the other three rollers, conveyor means operativelyassociated to advance a skin between the rollers of each pairsequentially; and a third pair of substantially coextensive rollerspositioned at the discharge end adjacent and above said conveyor meansto grip and apply a pulling force to hair while simultaneouslypreventing movement of the skin codirectionally With said pulling force.

6. Apparatus for dehairing skins comprising a conveyor for moving theskins, holes in said conveyor for inserting the shanks of the skin tohold the skin on the conveyor, a first set of rollers working incooperation with said conveyor to loosen the hair from the skins and asecondset of rollers both of which being located adjacent the conveyorand adapted to pull the loosened hair from the skin.

7. A method of separating wool from the skin to which it adheres whichcomprises: subjecting the pelt to be dewooled to the action of asolution of ammonium hydroxide; mechanically rubbing the surface of thepelt so treated to partially loosen the Wool; and thereafter placingsaid pelt so treated in a zone wherein said Wool is subjected to agripping and pulling force; and simultaneously therewith holding saidpelt whereby to prevent movement of the skin codirectionally with thesaid pulling force.

References Cited in the file of this patent UNITED STATES PATENTS2,143,422 Plass Jan. 10, 1939 2,151,930 Messing et a1. Mar. 28, 1939FOREIGN PATENTS 2,434 Australia of 1931 23,524 Great Britain of 1906307,063 Italy Apr. 11, 1933 OTHER REFERENCES Progress in LeatherScience: 1920-4945, British Leather Manufacturers Research Association,London, England (1948.)

